Prestack reverse-time migration of acoustic wave equations in VTI media

Abstract

Based on the first-order acoustic wave equations in vertical transversely isotropic (VTI) media [1], high-order finite-difference schemes for reverse-time extrapolation and the perfectly matched layer (PML) absorbing boundary condition for the equations are derived. Prestack reverse-time depth migration of acoustic wave equations in VTI media using excitation-time imaging condition by maximum amplitude criteria and normalized cross-correlation imaging condition is carried out. Numerical experiments of anisotropic Marmousi model show that prestack reverse-time depth migration of acoustic wave equations in VTI media has good imaging effect on complex models with steep dips and strong lateral velocity variation. Reverse-time migration imaging condition using normalized cross-correlation has better imaging effect. Additionally, the contrast between anisotropic and isotropic reverse-time migration profiles proves that better imaging results can be obtained using anisotropic migration algorithms for P-wave data acquired in anisotropic regions.